When science is used to inform practice, careful measurement based on clear conceptualization is the beginning of wisdom. In particular, gauging how well people are doing is basic to figuring out whether efforts to improve people's lives are succeeding. Cost-benefit analyses at the micro level and GDP at the aggregate level face serious challenges in dealing with non-market goods. (Both cost-benefit analyses and GDP account for some non-market goods but miss many others.) This matters particularly in monitoring the well-being of older individuals because non-market goods, such as health and the pleasure from social relationships and leisure-time activities, become especially important at later ages. The overall objective of this proposal is to lay a stronger foundation for extensive us of subjective well-being (SWB) data to monitor changes in overall health and well-being. While the proposed research focuses broadly on understanding SWB data and how it can best be used, the cornerstones of this proposal are (1) developing new sources of data on multidimensional SWB, and (2) developing a set of methods and the necessary complementary data to aggregate SWB data across different aspects of well-being into an overall measure of well-being. This proposal builds on a substantial body of prior work, as well as on many of the conclusions and recommendations of the report of the NIA's Panel on Measuring Subjective Well-Being in a Policy-Relevant Framework (Stone and Mackie, 2013). Phase 1 (Years 1-2) of the proposed research is focused on understanding and improving SWB questions (especially in health dimensions) and methods for aggregating the responses into overall measures. Phase 2 (Years 2-5) is focused on creating and developing web panels, with two waves of data on the levels of a large number of dimensions of well-being. The purpose of Phase 1 is to make the quality of the data collection in Phase 2-and the subsequent analysis-as high as possible. The many SWB measures that will be collected on the Understanding America Study (UAS) will include versions of all the commonly used SWB questions currently carried on major surveys, making direct comparisons possible. The new data resources will be from the UAS, a relatively new web panel founded by Arie Kapteyn at USC, and other data sources, including a New Zealand well-being survey being planned by the government of New Zealand. The data would be publicly available. An important virtue of the UAS and similar surveys is that, without needing a prior connection to the UAS, any serious researcher can easily arrange to have additional complementary data collected, at a reasonable cost in terms of additional funding.